Fair Value Measurements and Disclosures - Financial assets measured at fair value on non-recurring basis (Details) - Nonrecurring - Level 3 - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial assets measured at fair value on a nonrecurring basis
Mortgage servicing rights	$ 10,097	$ 4,647
SBA loan servicing rights	1,835	970
Impaired loans	2,458	2,998
Total	$ 14,390	$ 8,615

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant